Variable pitch propeller control and indicator



R. J. RATIE March 11, 1947.

VARIABLE rn'cu PROPELLBR comoL AND INDICATOR Filed April 11, 1941 4 Sheets-Sheet 1 lllllll INIVENTOR= RENEJEAN RATIE ATTORNEYS Max-ch11, 1947. R. J. RATIE 2,417,176

. VARIABLE PITCH PROPBLLER CONTROL AND IIQDIGATOR Filed April 11, 1941 4 Sheets-Shoat 2 .e Y M I! i 0\ ea Q L V :L w. g

, |NVENTOR=,

RENE JEAN RATIB JYM 4 ATTORNEYS Much 1947- R. J. RATIE; 2,417,176

VARIABLE PITCH PROPELLER CONTROL AND INDICATOR Filed April 11 1941 4 Sheets-Sheet 3 llwmjrolt Y Raw: .Tzmv RAT/E ATTO RNIY.

Patented Mar. 11, 1947 VARIABLE PITCH PROPELLElt CONTROL AND INDICATOR Rene Jean Rati, Montrouge, France; vested in the Attorney General of the United States Application April 11, 1941, Serial No. 388,128

- In France April 24, 1940 Claims. (01.170-163) The present invention concerns the control of the pitch variations in propellers in which the pitch is variable in flight, and of the type in which the blades, pivoting relatively to the hub are coupled by a. mechanism controlled by an electric motor having a circuit which, previously closed by the pilot, or by a regulator linked with the working speed of the engine driving the propeller, for effecting a variation of the pitch in one direction or in the other, is automatically cut off when the pitch has reached a predetermined value.

This electric motor can have two directions of operation or it can have a. single direction if a kinematic reverser is connected thereto. The first case is the most frequently adopted and it is the one which will be contemplated in the following' However, it is to be understood that the invention applies to both cases.

The invention is adapted tocombine, in one and the same apparatus of reduced dimensions, the elements indicated hereinafter, which, in known installations are either distinct or omitted in some cases, as follows:

Automatic control of the change of pitch in one direction or in the other;

Hand control of the change of pitch in one direction or in the other;

Independent adjustment of the amplitudes of the change of pitch in both directions:

The pitch indicator.

For this purpose, the apparatus forming the subject-matter of the invention is mainly characterised by the combination of three cams, viz:

A cam for automatically breaking the circuit of the motor at the end of the occurrence of change of pitch in one direction;

A cam for controlling the automatic breaking of the circuit of the motor at the end of the occurence of change of pitch in the other direction;

A cam having a double boss, capable of being controlled by hand, and comprising two bosses, one of which controls the circuit of the motor for one direction, the other, for the reverse direction; all three cams being constantly connected to the change pitch mechanism by planet pinions having a common gyration, the planet pinions of each cam meshing with a distinct sun wheel which allows: for the two first cams. the adjustment of the point of stoppage of the motor, for the third cam, the angular displacement of the latter from a member controlled by hand.

In a form of construction of the apparatus Iii drical case with a front face which carries a glass'plate through which can be seen the index of the pitch indicator, and the dimensions of which are extremely reduced.

The accompanying drawings illustrate, by way of example only, such a form of construction.

of the apparatus forming the subject-matter of the invention.

Fig. 1 is a diagram, with illustration'in perspective view, of the mechanical arrangement of the apparatus.

Fig. 2 is an electrical diagram of the operation of the entire control of the pitch variations.

Figure 3 is a sectional view through'an aeroplane propeller hub and adjacent engine casing, showing portions of my invention associated therewith.

Figure 4 is a sectional view taken through the propeller hub along the line 4-4 in Figure 3. and also showing the pitch control apparatus of Figure 1 connected to this hub.

Figure 5 is a sectional view taken along the line 55 in Figure 3.

For facilitating the illustration and description of the apparatus, the various parts have been arranged in Figure 1 by spacing them apart in the axial direction whereas in Figure 4 the parts are shown in their proper positions. It can be immediately seen that it is possible to bring them close together to group them into a case of reduced height. Neither the rear plate, nor the lateral wall of said case has been illustrated in Figure 1.

A shaft I is arranged according to the theoretical axis. of the entire apparatus and journalled at its ends, on the one hand, in the rear plate (Fig, 4) and, on the other hand, in a front plate 2 which, in this embodiment, constitutes the dial of the pitch indicating device. An index 3 rigidly secured on the shaft l moves over the dial 2 and it is intended to indicate, in direction and angular value. the changes of pitch. For that purpose, the shaft i is connected, by a flexible connection 4, I20 and I21 to the change pitch mechanism. This connection is such that shaft i is always in a specific angular position depending upon the pitch to which the propeller blades are adjusted. I

In Figures 3, 4 and there is shown in detail one example of a propeller hub and pitch change mechanism with which the present invention is adapted to be associated. In this example, the pitch change motor is mounted on the fuselage or engine casing, but it is evident that the present invention is not restricted to such "an arrangement. The variable pitch propeller mechanism shown in connection with the present invention is similar to that disclosed in the patent to MacCallum, No. 2,020,366 of November 12,

Referring to Figures 3, 4 and 5, the numeral IOI denotes a propeller hub which is mounted on the end of driving shaft I02, said hub having spindles I03 for supporting propeller blades I04.

Blades I04 rotate on bearings I05 disposed between proximate flanges on hub I M and blades I04 respectively.

v The gear mechanism for varying the pitch of the propellers ismounted in an oil case I06, which in turn, is secured to the fuselage or engine casing I01 by bolts I00. This gear system comprises a gear I09 fixedly secured to shaft I02, which gear drives idler gears I I0 rotatably mounted on stationary plate III forming the rear wall of the oil case I06. These idler gears IIO drive a double internal ring gear II 2, rotatably mounted between bearings I I3, said gear II2 driving a second set of idler gears II4 which are rotatably mounted upon worm gear wheel II5. Gears II4 are of the same diameter as the above-mentioned idler gears IIO. By referring to Figure 3, it is seen that gears II4 drive propeller blade I04 through a double gear H6, and a beveled gear II8. A worm H9 meshes with worm gear II5, said-worm being drivably connected to a motor 43 on engine casing I01 by means of a flexible connection I 2|.

During operation, the gear I09 drives gear H6 in the same direction and at the same speed as shaft I02, through the gears H0, H2 and H4 when worm gear H5 is held stationary. I When it is desired to decrease or increase the propeller pitch the worm gear H5 is rotated in a corresponding direction by members 43, I2I and H9 to thereby increase or decrease the speed of gear II 6 and produce rotation, of gears I I8 and associated blades I04.

The above-described pitch change mechanism is connected to the controlling apparatus shown in Figures 1 and 4 by means of a flexible connection 4, I20 and I2I. The'fiexible connection 4, I20 and I2I is, in this embodiment, connected by a pinion 5 to the gear 6 fast on shaft I.

A train comprising: the pinion 1 fast on shaft I, including counter-motion: gear Ii-pinion 9, and gear I0 rigid with the pinion II and loosely mounted on shaft I, connects the latter to two planet pinions I2 freely journalled on a frame or cage illustrated by rods I3, brackets- I3 and easing I3".

Said planet pinions I2 in engagement with the central sun wheel II mesh with the inner set of teeth of a fixed internal gear I4, so that the rotation of pinion II produces the gyration oi the planet pinions I2. This gyration is transmitted, by the members I3, I3 and I3 to groups of planet pinions I5-I6-I1.' Gear I4 is fixed to outer casing I30 by means of pins I 4.

The group I5 meshes with a central sun wheel is and with th inner set of teeth of an internal gear or cam I9.

22 and with the inner set of teeth of a cam 23.

The three sun wheels I8, 20, 22 are loosely mounted on shaft I. The sun wheel I3 is angularly connected to a hand control member which, in this embodiment, is the rotatable front part 24 of the case of the apparatus, said part comprising a glass plate 25 through which can be seen the dial 2. and the index 3 of th indicator. The front part 24 is illustrated in Fig. 4 in section and the actual structure is in the form of a cylindrical rim 24 carrying the glass plate 25 and rotatably mounted in the adjacent end of the case I30 of the apparatus. Within the case I30, the front part 24 is connected to sun wheel IS. The connection between I8 and 24 is illustrated by an arm 26 and a rod 21 which carries an index 20 arranged in front of the dial 2.

The sun wheels 20 and 22 are respectively connected, by pinions 29, 30 and worm 3|; and also by pinions 32, 33 and worm 34, to adjusting rods 35 and 36 which are adjusted, for instance by means of a screw-driver and which are locked in the position of adjustment chosen by said worms. The cam I9 (so-called hand cam) comprises two bosses I9 and I9 connected by inclines I 0 of neutral position. One of these bosses acts to .close a contact at 31, the other to close a contact at 38.

shown as having the same reference numbers as in Fig. 1. It will be noted by observing Fig. 3 that a speed responsive regulator designated by reference characters 44, 45 and 45 is provided, said regulator being driven by the shaft I02 through a gear train I3I, I32, I33 and I34.

The operation of the apparatus is as follows:

Case of automatic control This case is that in which the speed responsiv regulator linked with the working speed of the engine intervenes for producing the pitch variations which must allow the engine to resume its optimum working speed when it departs therefrom. If the working speed lowers, the pitch is diminished; if the working speed increases, the pitch is increased. The speed responsive regulator is of any known type.

For putting the electric motor 43 for the change of pitch under the control of the regulator, the pilot acts on a key 53 to close the contacts at 46 and 46 as shown in dotted lines. If the propeller rotates too rapidly, that is to say if the engine races, the regulator closes the contact at 44-45. A circuit is established through the positive pole of. the battery or source of current, contacts 44-45, contact 39. contact 46, winding of relay 48 and negative pole of the source. The relay 48 is energized and closes the contact at 49 which establishes the circuit exciting the motor 43 in the direction for increasing the pitch. This circuit is as follows: from the negative pole of the source of current, through contact 49, inductor 43, armature 43 and to the positiv pole of the source of current. The motor 43 rotates in the direction for increasing the pitch of the pro- 5 peller and drives, by the flexible connection above mentioned, the shaft 4 '(Fig. 1) which acts:

1. Through the medium of pinion 5 and gear 8, to drive shaft 1 which carries the index 3 and indicates to the pilot the direction and the amplitude or the change of pitch.

2. To drive, through the train 58-'l8- ll| the frame [3, l3 and I3 which carries the various planet pinions. The wheels 22 and 20 being stationary, both wheels 2| and 23 are rotatably driven and limit the evolution of the pitch of the propeller between two extreme values. Through the medium of the cam-boss 2|, the wheel 2| cuts of! the contact 33 of the circuit exciting relay 48, this breaking determining the maximum value of the pitch, which value is adjusted by acting on the rod 38, as explained above.

When the regulator acts for reducing the pitch, the contact is closed at 44-48 and. relay 48 is energized through 40-43 -4| The contact is closed a 43' and the inductor 43 is energized. The motor 43 rotates in the direction for reducing the pitch. It is stopped, either by the regulater which cuts oil the contact at 44-43, or by the cam-boss 23 which breaks the contact at 40 and determines the minimum value of the pitch.

Case of hand control If the pilot desires to give to the pitch the entire value he has chosen, he actuates the key 53 so as to close the contacts 5i and 52, the contacts at 46-48 being cut off. This operation has as its effect to put the motor 43 under the control of the contacts 31 and 38.

The pilot then moves the front part of the case 24 to bring the index 28 opposite the point of the graduation of thedial 2 corresponding to the pitch desired. The angular displacement thus efiected through the medium of the front part of the case24 is transmitted to the wheel l8 through the medium of the members 21-28 and the planet pinions 15. If the pilot has indicated on the dial 2, as just explained, a pitch greater than the initial pitch, the contact 38 is closed, which has the eifect, as can be seen on the diagram of Fig. 2, of energizing relay 48 and starting the motor 43 in the direction for increasing the pitch.

As already explained concerning the automatic change oi pitch, the flexible connection at 4,120 and Ill causes wheel I! to rotate through the medium of the train: 58l-8-9l0-H- l2-i5. As soon as wheel l9 has resumed its initial. position, which occurs when the index 3 has come opposite the index 28, the contact 38 During the time the device is under hand control, cams 2| and 23 exert no control effect because the circuits oi. switches 39 and are open at switches 48 and 46. apparatus is under automatic control, cam 19 exerts no control effect because the circuits of switches 31 and 38 are open at switches 8| and 82.

The apparatus according to the invention, lends itself by its very conception, to the association of the change pitch controls oi all the propellers of one and the same multi-engine aeroplane. It suiiices to juxtapose on one and the same board several apparatuses such as that described, by mechanically connecting, by means of suitable connections, the automatic and hand control members from one apparatus to the other. For the hand control of the change of pitch, in particular, it-sufilces for the pilot to act on a single movable dial such as 24 for givin the same pitch to all the propellers.

What I claim as my invention and desire to secure by Letters Patent ls:

1. Apparatus for controlling and indicating pitch variations of the blades of a propeller, in-

cluding a pitch changing motor having two control circuits for operating the same in opposite is cut oil and the change pitch movement is stopped.

The operation is identical when the pilot desires to pass from a given pitch to a smaller pitch. In this case, the contact 31 is closed and relay 43- is energized as well as the inductor 43.

Any automatic preselecting system intended to determine the optimum pitch can be combined with the hand control which has just been described.

It will be noted that the planet pinions I2- l5l6l1 being loosely mounted or freely journalled on the frame iii, the following operations: rotation of knob 35, rotation of knob 36, rotation of dial 24 for the hand control of cam l9, are absolutely independent from and do not afiect the gyration of the frame l3, l3 and I3. Said 8y ration occurs only it the pinion ll rotates, that is to say. ii the motor 43 rotates by modifying the setting of the blades.

directions, independent switch means in each of said circuits, a movable cam having means associated therewith and actuated thereby for opening the circuit of said motor to stop the same at the end of a pitch changing operation in one direction, a second movable cam also having means associated therewith for opening the circuit of said motor at the end of a pitch changing operation in the opposite direction, a third movable cam having two projections and associated means actuated thereby for selecting and operating either one of said control circuits so as to operate the motor accordingly for changing the pitch in either direction, a plurality of planet pinions arranged to have a common gyration, sun gears connected to and moving said cams. and means operatively communicating the pitch changing movement ,of the propeller blades to said sun gears.

2. Apparatus for controlling and indicating pitch variations of the blades of a propeller, in-

cluding a pitch changing motor having two coninternal gear teeth and having two projections and associated means actuated thereby for selecting and operating either one of said control circuits so as to operate the motor accordingly for changing the pitch in either direction, a shaftfor a pitch indicator disposed centrally with respect to the three sets of internal gear teeth, three pinions journalled on said shaft and each corresponding to a cam of the three, planet pinions disposed between and meshing with said pinions and said sets of internal gear teeth, a common mounting means for said planet pinions to cause them to have a common gyration, and means for operatively connecting said mounting means to the motor.

Conversely when the 7 v 3. Apparatus for controlling and indicating pitch variations ofthe blades of a propeller. in-

' eluding a pitch changing motor having two control circuits for operating the same in opposite directions, independent switch means in each of said circuits, a movable cam provided with internal gearteeth and having means associated ternal gear teeth and having two projections and associated means actuated thereby for selecting and operating either one'of said control circuits so as to operate the motor accordingly i'or changingv the pitch in either direction, a shaft for a pitch indicator disposed centrally with respect to the three sets of internal gear teeth, three pinions journalled on said shaft and each "corresponding to a cam 01' the three, two adjusting means for the first two cams, means for connecting said adjusting means individually to the two pinions on said shaft which correspond to said two first cams, planet pinions disposed between and meshing'with all of saidpinions and said sets of internal gear teeth, a common mounting means for said planet pinions to cause them to have a common gyration, and means for operatively connecting said mounting means to the motor.

4. Apparatus according to claim 2, having a casing for enclosing the members of the apparatus having a rotatable wall forming a manually operable control means for the pinions corresponding to the third cam. and means for transmitting movement of said wall to said pinion,

5. Apparatus according to claim 3, having a casing for enclosing the members of the apparatus having a rotatable wall forming a manually operable control means for the pinions corresponding to the third cam, and means for transmitting movement of said wall to said pinion.

RENE JEAN RATIE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,907,014 Sperry May 2, 1933 1,958,261 Blanchard May 8, 1934 1,968,029 Couch July 31, 1934 2,020,366 MacCallum Nov. 12, 1935 2,127,687 Heath Aug, 23,1938 2,155,586 Ebert Apr. 25, 1939 2,187,364 Rati Jan. 16, 1940 2,228,776 Mullen Jan. 14, 1941 2,232,753 Wilson Feb, 25, 1941 FOREIGN PATENTS Number Country Date 352,906 Italian Sept. 25, 1937 451,520 British Aug. '7, 1936 

